Vorrichtung zur Freistrahlübertragung von Energie und Information

Die Erfindung betrifft eine Vorrichtung zur Freistrahlübertragung von Energie und Information umfassend zumindest ein erstes Laserelement (2), optische Mittel (2.1, 3.1, 4), sowie zumindest ein zweites Laserelement, wobei zumindest das erste Laserelement (2), das zweite Laserelement und die optischen Mittel (2.1, 3.1, 4) derart zusammenwirkend ausgebildet und angeordnet sind, dass sich eine Laserstrahlung (7) des ersten Laserelements (2) und eine Laserstrahlung (8) des zweiten Laserelements (3) in einem Fernfeld überlagern. Wesentlich ist, dass zumindest das erste Laserelement (2) und die optischen Mittel (2.1, 3.1, 4) mittelbar oder unmittelbar auf einer gemeinsamen Entwärmungsstruktur (6) angeordnet und mit dieser thermisch leitend verbunden sind, wobei durch die gemeinsame Entwärmungsstruktur (6) ein im wesentlichen isothermes Temperaturniveau für zumindest das erste Laserelement (6) und die optischen Mittel (2.1, 3.1, 4) auf der gemeinsamen Entwärmungsstruktur (6) einstellbar ist

Modeling the Electro-Optical Performance of High Power Mid-Infrared Quantum Cascade Lasers

Performance modeling of the characteristics of mid-infrared quantum cascade lasers (MIR QCL) is an essential element in formulating consistent component requirements and specifications, in preparing guidelines for the design and manufacture of the QCL structures, and in assessing different modes of operation of the laser device. We use principles of system physics to analyze the electro-optical characteristics of high power MIR QCL, including thermal backfilling of the lower laser level, hot electron effects, and Stark detuning during lasing. The analysis is based on analytical modeling to give simple mathematical expressions which are easily incorporated in system-level simulations of defense applications such as directed infrared countermeasures (DIRCM). The paper delineates the system physics of the electro-optical energy conversion in QCL and the related modeling. The application of the performance model to a DIRCM QCL is explained by an example

100 W-level peak power laser system tunable in the LWIR applied to detection of persistent chemical agents

Through the European Defence Agency, the Joint Investment Programme on CBRN protection funded the project AMURFOCAL to address detection at stand-off distances with amplified quantum cascade laser technology in the longwave infrared spectral range, where chemical agents have specific absorptions features. An instrument was developed based on infrared backscattering spectroscopy. We realized a pulsed laser system with a fast tunability from 8 to 10 μm using an external-cavity quantum cascade laser (EC-QCL) and optical parametric amplification (OPA). The EC-QCL is tunable from 8 to 10 μm and delivers output peak powers up to 500 mW. The peak power is amplified with high gain in an orientation-patterned gallium arsenide (OP-GaAs) nonlinear crystal. We developed a pulsed fiber laser acousto-optically tunable from 1880 to 1980 nm with output peak powers up to 7 kW as pump source to realize an efficient quasi-phase matched OPA without any mechanical or thermal action onto the nonlinear crystal. Mixing the EC-QCL and the pump beams within the OP-GaAs crystal and tuning the pump wavelength enables parametric amplification of the EC-QCL from 8 to 10 μm leading to up to 120 W peak power. The output is transmitted to a target at a distance of 10 – 20 m. A receiver based on a broadband infrared detector comprises a few detector elements. A 3D data cube is registered by wavelength tuning the laser emission while recording a synchronized signal received from the target. The presentation will describe the AMURFOCAL instrument, its functional units and its principles of operation

First results of a QCL-OPA based standoff system, for detecting hazardous substances in the IR-fingerprint domain

Within the framework of the first European Defence Agency (EDA) call for protection against chemical, biological, radiological and nuclear threats (CBRN Protection) we established a project on active multispectral reflection fingerprinting of persistent chemical agents (AMURFOCAL). A first paper on the project AMURFOCAL has been issued last year on the SPIE conference in Warsaw, Poland. This follow up paper will be accompanied by an additional paper that deals specifically with the aspect of the 100 W-level peak power laser system tunable in the LWIR. In order to close a capability gap and to achieve detection at stand-off distances our consortium built a high peak power pulsed laser system with fast tunability from 8 to 10 μm using an external-cavity quantum cascade laser and optical parametric amplification. This system had to be tested against different substances on various surfaces with different angles of inclination to evaluate the ability for an active stand-off technology with an eye-safe laser system to detect small amounts of hazardous substances and residues. The scattered light from the background surface interferes with the signal originating from the persistent chemicals. To account for this additional difficulty new software based on neutral networks was developed for evaluation. The paper describes the basic setup of the instrument and the experiments as well as some first results for this technology